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Re: Thoriated Tungsten vs Pure
> Date: Sat, 28 Sep 1996 22:25:08 -0600
> From: Tesla List <tesla-at-poodle.pupman-dot-com>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject: Re: Thoriated Tungsten vs Pure
> Reply-to: tesla-at-pupman-dot-com
> >From ed-at-alumni.caltech.eduSat Sep 28 21:36:18 1996
> Date: Sat, 28 Sep 1996 15:21:59 -0700 (PDT)
> From: "Edward V. Phillips" <ed-at-alumni.caltech.edu>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com, tesla-at-pupman-dot-com
> Subject: Re: Thoriated Tungsten vs Pure
>
> Thoriated tungsten is used for tube filaments because it hnas
> has much higher emission at lower temperatures than pure tungsten,
> hence lasts much longer. Effect was discovered accidently in the
> early 1920's. Thorium was originally added to light bulb filaments
> "to make them easier to draw through the wire dies" (per RCA
> Vaccum Tube Design Manual, circa 1940).
> Can't prove it, but suspect the radioactivity is barely detectable,
> and certainly not a health hazard.
> Ed Phillips
>
That is not quit true. Thoriated tungsten such as are used in TIG
welding do not cause a health hazard except under continous inhaling
of the vaporized metal for many years. (Welders can get lung cancer
from long term exposure.) Or... that large quatities of the
electrodes are not stored in close proximity to a persons body.
Casual use of the rods pose no health hazards that are known. But it
is another thing to be exposed to the fumes and or a large quantity
of the electrodes. A geiger counter will go crazy with full box of
them. (Just try it!) Welders that do alot of TIG welding should protect
themselves for the vapors and against carrying boxes of them in their shirt
pocket (Like so many are prone to do.)
Chris Singletary
member - TCBA
Believe that you CAN accomplish the impossible and you shall.